Were was this found..(country) it looks very much like a medieval Anular Brooch...an those marks won't be a makers mark...but decrotive, it looks Silver to.
UK Finds Database - - - UKDFD
Problem is, most Annular Brooches are from the 13-14th C. However, as yours has some kind of makers marks which the early type never had, it suggests a later date.
I can you give you a value based on it being a 14th C Silver Annular Brooch - $100. BUT, being a US find, its got me stumped, an expert needs to see it in person, to tell up close what age it is!
Check out your county, or where ever you found it, find out when the first settlers moved into that area.
Find out when the first white explores got to that area, you know we all came from across the pond, Unless
your Native American, If found at a 1700's home it could have been a family heirloom. jmho............HH